Mitsubishi Lancer Evolution IX. Manual - part 423

TROUBLESHOOTING

MULTIPORT FUEL INJECTION (MPI)

13A-167

FUNCTION

• The exhaust camshaft position sensor detects 

the top dead center on the compression stroke of 
the No. 1 cylinder and inputs a pulse signal to the 
engine-ECU.

TROUBLE JUDGMENT

Check Conditions

• Ignition switch: "ON" 

• Engine speed of 50 r/min. or more.

Judgment Criterion

• The sensor output voltage remains unchanged 

(no pulse signal is inputted) for 2 seconds.

PROBABLE CAUSES

• Failed exhaust camshaft position sensor 

• Open/short circuit in exhaust camshaft position 

sensor circuit or loose connector contact

• Failed engine-ECU

DIAGNOSIS PROCEDURE

STEP 1. Connector check: B-106 exhaust 
camshaft position sensor connector

Q: Is the check result normal? 

YES : 

Go to Step 2 .

NO : 

Repair or replace the connector.

STEP 2. Perform voltage measurement at B-106 
exhaust camshaft position sensor connector.

• Disconnect connector, and measure at harness 

side.

• Ignition switch: "ON" 

• Voltage between terminal No. 3 and earth.

OK: System voltage

Q: Is the check result normal? 

YES : 

Go to Step 4 .

NO : 

Go to Step 3 .

AK501999

1

2

3

AB

Connector: B-106

B-106 (B)

Harness side 
connector

AK501999

1

2

3

AB

Connector: B-106

B-106 (B)

Harness side 
connector

TROUBLESHOOTING

MULTIPORT FUEL INJECTION (MPI)

13A-168

STEP 3. Connector check: B-12X engine control 
relay connector

Q: Is the check result normal? 

YES : 

Check and repair harness between B-106 

(terminal No. 3) exhaust camshaft position 
sensor connector and B-12X (terminal No. 
4) engine control relay connector.

• Check power supply line for 

open/short circuit.

NO : 

Repair or replace the connector.

STEP 4. Perform voltage measurement at B-106 
exhaust camshaft position sensor connector.

• Disconnect connector, and measure at harness 

side.

• Ignition switch: "ON" 

• Voltage between terminal No. 2 and earth.

OK: 4.9 

− 5.1 V

Q: Is the check result normal? 

YES : 

Go to Step 10 .

NO : 

Go to Step 5 .

AK305003

2

1

3

4

AB

Connector : B-12X

B-12X

Harness side 
connector

Relay box’s
triangle marks

AK501999

1

2

3

AB

Connector: B-106

B-106 (B)

Harness side 
connector

AK501999

1

2

3

AB

Connector: B-106

B-106 (B)

Harness side 
connector

TROUBLESHOOTING

MULTIPORT FUEL INJECTION (MPI)

13A-169

STEP 5. Perform voltage measurement at C-119 
engine-ECU connector.

• Measure engine-ECU terminal voltage.

• Disconnect B-106 exhaust camshaft position sen-

sor connector.

• Ignition switch: "ON" 

• Voltage between terminal No. 50 and earth.

OK: 4.9 

− 5.1 V

Q: Is the check result normal? 

YES : 

Go to Step 6 .

NO : 

Go to Step 7 .

STEP 6. Connector check: C-119 engine-ECU 
connector

Q: Is the check result normal? 

YES : 

Check and repair harness between B-106 

(terminal No. 2) exhaust camshaft position 
sensor connector and C-119 (terminal No. 
50) engine-ECU connector. 

• Check output line for open circuit.

NO : 

Repair or replace the connector.

AK501994

65

43
50

42
49

41
48
60

61

64

46

47

58

59

67

68

45

56
66

52 51

44

53

62

54

63

57

55

AB

Connector: C-119

C-119 (GR)

C-119 (GR)

Harness side connector

<L. H. drive vehicles>

<R. H. drive vehicles>

AK501999

1

2

3

AB

Connector: B-106

B-106 (B)

Harness side 
connector

AK501994

65

43
50

42
49

41
48
60

61

64

46

47

58

59

67

68

45

56
66

52 51

44

53

62

54

63

57

55

AB

Connector: C-119

C-119 (GR)

C-119 (GR)

Harness side connector

<L. H. drive vehicles>

<R. H. drive vehicles>

AK501999

1

2

3

AB

Connector: B-106

B-106 (B)

Harness side 
connector

TROUBLESHOOTING

MULTIPORT FUEL INJECTION (MPI)

13A-170

STEP 7. Connector check: C-119 engine-ECU 
connector

Q: Is the check result normal? 

YES : 

Go to Step 8 .

NO : 

Repair or replace the connector.

STEP 8. Check harness between B-106 (terminal 
No. 2) camshaft position sensor connector and 
C-119 (terminal No. 50) engine-ECU connector.

• Check output line for short circuit.

Q: Is the check result normal? 

YES : 

Go to Step 9 .

NO : 

Repair the damaged harness wire.

STEP 9. Check the trouble symptoms.

Q: Does trouble symptom persist?

YES : 

Replace the engine-ECU. 

NO : 

Intermittent malfunction (Refer to GROUP 
00 

− How to Use 

Troubleshooting/Inspection Service Points 

P.00-5

).

AK501994

65

43
50

42
49

41
48
60

61

64

46

47

58

59

67

68

45

56
66

52 51

44

53

62

54

63

57

55

AB

Connector: C-119

C-119 (GR)

C-119 (GR)

Harness side connector

<L. H. drive vehicles>

<R. H. drive vehicles>

AK501999

1

2

3

AB

Connector: B-106

B-106 (B)

Harness side 
connector

AK501994

65

43
50

42
49

41
48
60

61

64

46

47

58

59

67

68

45

56
66

52 51

44

53

62

54

63

57

55

AB

Connector: C-119

C-119 (GR)

C-119 (GR)

Harness side connector

<L. H. drive vehicles>

<R. H. drive vehicles>